1. Of a random sample of 900 trucks at a bridge, 360 had bad signal lights. Construct a 99 percent confidence interval for the percentage of trucks that had bad signal lights.

2.Suppose that 80 percent of the voters in a particular region support a candidate. Find the probability that a sample of 1600 voters would yield a sample proportion in favor of the candidate within 1 percentage points of the actual proportion.

3. True or False:

If a population is known to be normally distributed, then it follows that the sample mean must equal the population mean.